203 lines
6.4 KiB
Go
203 lines
6.4 KiB
Go
package radarfetch
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import (
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"fmt"
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"os"
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"path/filepath"
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"time"
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)
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// StartJob launches a background ticker to download NMC images and CMA bin using Huanan time.
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type Options struct {
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OutRoot string
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TZOffset int
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Interval time.Duration
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NMCChinaURL string
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NMCHuananURL string
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NMCNanningURL string
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CMABase string
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Z, Y, X int
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}
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// RunOnce executes a single download-render-save cycle.
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func RunOnce(opts Options) error {
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if opts.OutRoot == "" {
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opts.OutRoot = "./radar_data"
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}
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if opts.TZOffset == 0 {
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opts.TZOffset = 8
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}
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if opts.NMCChinaURL == "" {
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opts.NMCChinaURL = "https://www.nmc.cn/publish/radar/chinaall.html"
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}
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if opts.NMCHuananURL == "" {
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opts.NMCHuananURL = "https://www.nmc.cn/publish/radar/huanan.html"
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}
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if opts.NMCNanningURL == "" {
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opts.NMCNanningURL = "https://www.nmc.cn/publish/radar/guang-xi/nan-ning.htm"
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}
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if opts.CMABase == "" {
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opts.CMABase = "https://image.data.cma.cn"
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}
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if opts.Z == 0 && opts.Y == 0 && opts.X == 0 {
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opts.Z, opts.Y, opts.X = 7, 40, 102
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}
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fmt.Printf("[radar] start run: out=%s z/y/x=%d/%d/%d tz=%d\n", opts.OutRoot, opts.Z, opts.Y, opts.X, opts.TZOffset)
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err := runDownload(opts.OutRoot, opts.TZOffset, opts.NMCChinaURL, opts.NMCHuananURL, opts.NMCNanningURL, opts.CMABase, opts.Z, opts.Y, opts.X)
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if err != nil {
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fmt.Printf("[radar] run failed: %v\n", err)
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return err
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}
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fmt.Println("[radar] run done")
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return nil
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}
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// Run starts the periodic downloader (blocking ticker loop).
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func Run(opts Options) {
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if opts.OutRoot == "" {
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opts.OutRoot = "./radar_data"
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}
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if opts.TZOffset == 0 {
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opts.TZOffset = 8
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}
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if opts.Interval <= 0 {
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opts.Interval = 10 * time.Minute
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}
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if opts.NMCChinaURL == "" {
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opts.NMCChinaURL = "https://www.nmc.cn/publish/radar/chinaall.html"
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}
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if opts.NMCHuananURL == "" {
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opts.NMCHuananURL = "https://www.nmc.cn/publish/radar/huanan.html"
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}
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if opts.NMCNanningURL == "" {
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opts.NMCNanningURL = "https://www.nmc.cn/publish/radar/guang-xi/nan-ning.htm"
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}
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if opts.CMABase == "" {
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opts.CMABase = "https://image.data.cma.cn"
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}
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if opts.Z == 0 && opts.Y == 0 && opts.X == 0 {
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opts.Z, opts.Y, opts.X = 7, 40, 102
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}
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_ = RunOnce(opts)
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t := time.NewTicker(opts.Interval)
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for range t.C {
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_ = RunOnce(opts)
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}
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}
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func runDownload(outRoot string, tzOffset int, chinaURL, huananURL, nanningURL, cmaBase string, z, y, x int) error {
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// 1) Fetch NMC pages and parse image/time (time from Huanan)
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fmt.Println("[radar] fetch NMC China page ...")
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chinaHTML, err := GetWithUA(chinaURL, DefaultUA, 15*time.Second, nil)
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if err != nil {
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return fmt.Errorf("fetch NMC China: %w", err)
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}
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chinaImg, _, ok := ExtractFirstImageAndTime(chinaHTML)
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if !ok {
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return fmt.Errorf("parse China page: data-img not found")
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}
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fmt.Println("[radar] fetch NMC Huanan page ...")
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huananHTML, err := GetWithUA(huananURL, DefaultUA, 15*time.Second, nil)
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if err != nil {
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return fmt.Errorf("fetch NMC Huanan: %w", err)
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}
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huananImg, huananTime, ok := ExtractFirstImageAndTime(huananHTML)
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if !ok {
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return fmt.Errorf("parse Huanan page: data-img not found")
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}
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date, hour, minute, tsLocal := ParseNmcTime(huananTime, tzOffset)
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fmt.Println("[radar] fetch NMC Nanning page ...")
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nanningHTML, err := GetWithUA(nanningURL, DefaultUA, 15*time.Second, nil)
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if err != nil {
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return fmt.Errorf("fetch NMC Nanning: %w", err)
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}
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nanningImg, _, ok := ExtractFirstImageAndTime(nanningHTML)
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if !ok {
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return fmt.Errorf("parse Nanning page: data-img not found")
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}
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// Prepare out directory
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outDir := filepath.Join(outRoot, fmt.Sprintf("%04d%02d%02d", date/10000, (date/100)%100, date%100), fmt.Sprintf("%02d", hour), fmt.Sprintf("%02d", minute))
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if err := os.MkdirAll(outDir, 0o755); err != nil {
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return fmt.Errorf("mkdir outDir: %w", err)
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}
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// Download three images (with Referer)
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imgHeaders := map[string]string{
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"Referer": "https://www.nmc.cn/",
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"Accept": "image/avif,image/webp,image/apng,image/*,*/*;q=0.8",
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}
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fmt.Println("[radar] download China/Huanan/Nanning images ...")
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if b, err := GetWithUA(chinaImg, DefaultUA, 20*time.Second, imgHeaders); err == nil {
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_ = os.WriteFile(filepath.Join(outDir, "nmc_chinaall.png"), b, 0o644)
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}
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if b, err := GetWithUA(huananImg, DefaultUA, 20*time.Second, imgHeaders); err == nil {
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_ = os.WriteFile(filepath.Join(outDir, "nmc_huanan.png"), b, 0o644)
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}
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if b, err := GetWithUA(nanningImg, DefaultUA, 20*time.Second, imgHeaders); err == nil {
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_ = os.WriteFile(filepath.Join(outDir, "nmc_nanning.png"), b, 0o644)
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}
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// 2) Fetch CMA BIN with Huanan time
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binURL := BuildCMAURL(cmaBase, date, hour, minute, z, y, x)
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binHeaders := map[string]string{
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"Referer": "https://data.cma.cn/",
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"Origin": "https://data.cma.cn",
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"User-Agent": DefaultUA,
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"Accept": "*/*",
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}
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fmt.Printf("[radar] download CMA bin z/y/x=%d/%d/%d ...\n", z, y, x)
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binBytes, err := GetWithUA(binURL, DefaultUA, 30*time.Second, binHeaders)
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if err != nil {
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return fmt.Errorf("fetch BIN: %w", err)
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}
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binPath := filepath.Join(outDir, fmt.Sprintf("%d-%d-%d.bin", z, y, x))
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if err := os.WriteFile(binPath, binBytes, 0o644); err != nil {
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return fmt.Errorf("save BIN: %w", err)
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}
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// Render BIN -> PNG
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cmaPNG := filepath.Join(outDir, fmt.Sprintf("cma_%d-%d-%d.png", z, y, x))
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fmt.Println("[radar] render bin -> png ...")
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if err := RenderBinToPNG(binPath, cmaPNG, true); err != nil {
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return fmt.Errorf("render PNG: %w", err)
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}
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// 3) Write metadata and update latest
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w, s, e, n, res := Bounds4326(z, y, x)
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meta := Metadata{
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TimestampLocal: tsLocal,
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Date: date,
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Hour: hour,
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Minute: minute,
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Z: z,
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Y: y,
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X: x,
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Bounds: Bounds{West: w, South: s, East: e, North: n},
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ResDeg: res,
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Sources: Sources{NmcHTML: huananURL, NmcImg: huananImg, CmaBin: binURL},
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Files: Files{HTML: "", PNG: filepath.Join(outDir, "nmc_huanan.png"), BIN: binPath, Metadata: filepath.Join(outDir, "metadata.json"), CMAPNG: cmaPNG},
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Sizes: Sizes{PNG: fileSize(filepath.Join(outDir, "nmc_huanan.png")), BIN: int64(len(binBytes))},
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CreatedAt: time.Now().Format(time.RFC3339),
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}
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if err := WriteMetadata(filepath.Join(outDir, "metadata.json"), &meta); err != nil {
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return fmt.Errorf("write metadata: %w", err)
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}
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fmt.Println("[radar] update latest snapshot ...")
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if err := UpdateLatest(outRoot, outDir, &meta); err != nil {
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return fmt.Errorf("update latest: %w", err)
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}
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return nil
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}
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func fileSize(p string) int64 {
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fi, err := os.Stat(p)
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if err != nil {
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return 0
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}
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return fi.Size()
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}
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